diff --git a/tox.ini b/tox.ini
index 74d17e7f0..eb5c8f3e5 100644
--- a/tox.ini
+++ b/tox.ini
@@ -25,3 +25,4 @@ max-line-length = 120
 ignore = E121,E126,E241,FI12,FI14,FI15,FI50,FI51,FI53,FI54,FI55
 exclude = build
 require-code = True
+min-version = 2.7